SolidWorks 2011 Assemblies Bible - Matt Lombard [49]
FIGURE 5.13
Applying a Gear mate
Rack and Pinion mate
The Rack and Pinion mate takes rotational motion of one part and turns it into translational motion for a second part. Again, the parts do not need to be physically connected and can be simple representations of the actual geometry that is needed to drive the motion in the real world. Figure 5.14 shows an assembly that uses the Rack and Pinion mate. You can find this assembly on the DVD with the filename RackPinionMate.sldasm.
FIGURE 5.14
Applying a Rack and Pinion mate
Limit mates
You can apply limits to distance and angle mates in order to allow the parts to move within a certain range of values. Figure 5.15 shows the PropertyManager interface for the Limit Angle mate. Limit mates accept zero and negative values that are not normally accepted for dimensions in SolidWorks. When used properly, Limit mates can be an extremely powerful tool for creating more realistic motion in assemblies.
FIGURE 5.15
The LimitAngle PropertyManager
On the DVD, open the assembly named Robot Limit Mate.sldasm. Drag the Robot Tower part. Notice that it only rotates within a limited angle. LimitAngle2 is the mate that is driving this motion.
Screw mate
The Screw mate functions just the way the name suggests. For every revolution of a part relative to another part, the part moves in a linear direction by a specified amount. This mate requires two cylindrical faces and a pitch value, as shown in Figure 5.16.
FIGURE 5.16
Setting up a Screw mate
Screw mates can be handy for lead screw animations. Although they are not recommended for general modeling, for animations, they are a fantastic addition to the mate toolbox.
Path mate
The Path mate is the one that makes complex barrel cam motion possible, as well as other types of path-driven motion. Another application for this mate type beyond barrel cams is for the motion of a camera in a fly-through animation. The Path mate requires a point or vertex on one part and a curve selection on a second part. If the path selection is not just a single sketch or curve entity, it requires the use of the SelectionManager, which enables you to select multiple end-to-end entities to form closed or open paths. Figure 5.17 shows the setup for a Path mate.
FIGURE 5.17
Setting up a Path mate
Note
On the barrel cam in Figure 5.17, notice that a sketch point is being driven along the path. In reality, this does not exactly reflect the motion of the follower around the cam surface. The Path mate does not take into account the tangent contact point between the surfaces; it simply drives the point along the curve. There is a slight amount of error in this scenario, such that the leading or trailing surface of the follower will interfere with the cam on angled slopes, depending on the angle of the cam surface. Also note that the Path sketch entity has nothing to do with the Path mate; it is not required to make the Path mate work.
Linear Coupler mate
The Linear Coupler mate relates the motion of one part in one direction to another part in either the same or a different direction. It also enables you to apply a ratio between the motions. The directions do not have to be parallel or anti-parallel; they can be at right angles, or at any angle. The mate only controls motion in one direction, so other directions are free to move.
You can use this mate to simulate symmetric motion or geared motion without modeling the rest of the detailed mechanism. Figure 5.18 shows the setup for this mate.
FIGURE 5.18
Setting up a Linear Coupler mate
Hinge mate
The Hinge mate is just a shortcut for making a Concentric and a Coincident mate, but it does it all in a single feature and a single